The coal seams in the Highveld Coalfield are generally described as flat lying to gently undulating, with a regional dip to the south. The depth of the coal seams increases in a southerly direction. The Highveld coalfield has been affected by numerous dolerite dykes and sills related to the Drakensberg Formation flood basalts. Within the vicinity of the dolerite, the usual structural complications and devolatilization of the coal occurs.

At surface, the soils are described as sandy loams to sandy clay loams. Towards the south, the soil type becomes a dark grey sandy clay, due to the weathering of the underlying dolerite sill. Any outcrops or sub-crops are dominated by sedimentary rocks of the Ecca Group (Vryheid Formation).

The depth of weathering ranges from less than 1.0 m to almost 30 m in a few isolated holes located within the low-lying areas. The weathered zone predominantly comprises a grey-brown sandstone, with minor clay rich intercalations. The impact that the deeply weathered areas may have on the stability of the highwall within the current opencast areas has been reviewed. The resistivity data derived from the Dighem survey was compared to the point data from the drill holes in order to produce a continuous, calibrated surface representing the interface of soft and hard interburden. This surface was included in the geological model to allow a more precise estimation of volumes of the various materials.

In order to model the weath ........

The colliery is an opencast operation consisting of a north pit and a south pit. Both pits support a dragline operation and are assisted by a pre-strip truck and shovel fleet. The main equipment used in the pits includes two draglines, hydraulic shovels, haul trucks, dozers, excavators, rotary drills, water bowsers and cranes with the required ancillary support equipment. The mine layout was designed to suit the available mining equipment. The revised mining schedule accelerates the mining of the south pit due to lower costs, with reserves converted to resources outside mine plan (RoMP) in the north pit, due to constraints in the financial and economic modifying factors related to the CSA with Sasol coming to an end in 2025. A potential new CSA is currently being discussed. The remaining LOM is estimated at three years with total ROM reserves of 12.6Mt. There are no Inferred Coal Resources included in the LOM plan. The terms of the supply agreement with Sasol determines the LOM. The main target coal seam is the No 4 Seam, although the No 5 Seam. The open pit is designed for dragline operations and in the case of the North Pit the dragline is assisted by a prestrip truck shovel operation. The blocks are designed at 60 m wide by 150 m long. The mining method in the North Pit is designed to mine a combined total thickness of approximately 65 m which is split into approximately six metres of soft overburden material mined with a hydraulic excavator along with 16 m of hard ........

- subscription is required.

- subscription is required.